With its 11.6m high white painted buck, Stocks Mill at Wittersham is the tallest post mill in Kent. It was named after the local stocks, which stood nearby.

This is a turret-type post mill, which means it has a roundhouse protecting its trestle base, in this case single storey in brick. It didn't appear on maps of 1769, 1778 or 1801, though it is known to have existed in 1792, when it belonged to Thomas Howards. It is thought to have been moved to this site in 1781, since the main post has three inscriptions: "RV 1781", "RA 1785" and "IB 1790". It was last wind worked in 1882.

The mill is in good repair and has a rather rare brake, with wood below and iron above the centreline. The cast iron windshaft is square in section. The 2.7m brake-wheel has 120 wooden cogs, and the tail-wheel measures 2.4m. There were two pairs of overdrift stones set in 'head and tail' configuration. There used to be a belt-driven sack hoist.

The mill's buck, or body, has a slightly curved gabled roof, and there are four anticlockwise sweeps (sails) — two of which are controlled by springs — a tail ladder and tailpole with talthur (small beam used to hook the tailpole to the ladder), and the black tarred roundhouse with a timber roof.

Four new sweeps were fitted by local craftsman H. Payne in 1958. In 1968, one of the sweep support timbers broke in a storm, requiring further work by millwright Derek Ogden of Great Alne. Spring sweeps complete with shutters were still in place in 1979 but little internal machinery. Kent County Council took over 1980 and began external restoration.

Other points of interest include an 18th century fire mark of the Royal Exchange Insurance Company and a sliding trapdoor in the stone floor (the floor where the millstones would be) that closes automatically using a rope and pulley with a counterweight.

The mill is inspected annually, and the sweeps are turned through 90 degrees, though the mill itself is fixed in position.